This is the science and art of making a hole (otherwise called a well or wellbore) from the surface through a rock (or formation) to target potential hydrocarbon-bearing rock in the sub-surface. The general objective is to safely drill a useable hole that can give maximum production at minimum cost. Drilling operations account for over 80% of the total cost of a well. In many regions around the world especially the Gulf of Mexico, Gulf of Guinea and the North Sea, daily operational cost of an offshore rig range from $1 million to $1.5 million. This high cost has underlined the necessity for sound well planning and cost management to ensure that wells are drilled at lowest possible costs. Reference: SPE 0161
Drilling engineers design and implement procedures to drill wells as safely and economically as possible. They work closely with the drilling contractor, service contractors, and compliance personnel, as well as with geologists and other technical specialists. The drilling engineer has the responsibility for ensuring that costs are minimized while getting information to evaluate the formations penetrated, protecting the health and safety of workers and other personnel, and protecting the environment. 
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